Black Decker Inc.

Karl Schekulin

Klaus Kalbacher

Horst Grossmann

Claus Kolesch

A rotary hammer has a reciprocating piston of a pneumatic impact mechanism driven from a rotatable drive shaft. A coupling element is fixed on, and a drive element slidably mounted on, the drive shaft. These elements have interengageble tapered coupling surfaces and are biased apart by a spring therebetween. The drive element is disposed forwardly of the coupling element and is slidable rearwardly to drivingly engage the coupling surfaces for transmitting drive to the piston. The relative disposition of the drive and coupling elements causes reaction force on the piston, consequential in use upon generation of percussive blows, to urge the drive element into intensified engagement with the coupling element.

Rotary hammer driving mechanism

A rotary hammer with a pneumatic impact mechanism carries on a drive shaft, non-rotatably and non-displaceable axially relative thereto, a coupling element as well as, rotatably and displaceable axially relative thereto, a drive element. The drive element has a peripheral drive fin constituting a cam/control curve which engages between two rollers. The rollers are mounted on the rear end of a piston of the pneumatic impact mechanism with their axes of rotation perpendicular to the longitudinal axis of the piston. The drive element can at choice be brought into engagement with the coupling element. A manually operable control member may be operated to maintain the drive element out of such engagement.

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Munich, Georgia

Karl Schekulin